Projections of fire probability and ecosystem vulnerability under 21st century climate across a trans-Andean productivity gradient in Patagonia.

Warming trends are altering fire regimes globally, potentially impacting on the long-term persistence of some ecosystems. However, we still lack clear understanding of how climatic stressors will alter fire regimes along productivity gradients. We trained a Random Forests model of fire probabilities across a 5°lat × 2° long trans-Andean rainfall gradient in northern Patagonia using a 23-year long fire record and biophysical, vegetation, human activity and seasonal fire weather predictors. The final model was projected onto mid- and late 21st century fire weather conditions predicted by an ensemble of GCMs using 4 emission scenarios. We finally assessed the vulnerability of different forest ecosystems by matching predicted fire return intervals with critical forest persistence fire return thresholds developed with landscape simulations. Modern fire activity showed the typical hump-shaped relationship with productivity and a negative distance relationship with human settlements. However, fire probabilities were far more sensitive to current season fire weather than to any other predictor. Sharp responsiveness of fire to the accelerating drier/warmer fire seasons predicted for the remainder of the 21st century in the region led to 2 to 3-fold (RCPs 4.5 and 8.5) and 3 to 8-fold increases in fire probabilities for the mid- and late 21st century, respectively. Contrary to current generalizations of larger impacts of warming on fire activity in fuel-rich ecosystems, our modeling results showed first an increase in predicted fire activity in less productive ecosystems (shrublands and steppes) and a later evenly amplified fire activity-productivity relationship with it shape resembling (at higher fire probabilities) the modern hump-shaped relationship. Despite this apparent homogeneous effect of warming on fire activity, vulnerability to predicted late 21st century shorter fire intervals were higher in most productive ecosystems (subalpine deciduous and evergreen Nothofagus-dominated rainforests) due to a general lack of fire-adapted traits in the dominant trees that compose these forests.

Can persuasive and demonstrative messages to visitors reduce littering in river beaches?

Littering of public areas is a significant problem worldwide. Here we evaluate the success of persuasive and demonstrative messages at reducing littering in highly visited river beaches in Argentina. We made an intervention at the beaches which consisted of a personalized verbal request asking visitors to take their litter to the waste cans (persuasive message) while they were exposed to the example of picking up the litter already left on the beach (demonstrative message). We conducted 102 observations distributed over 29 dates, two years and four beaches. Each observation consisted of three or four rounds: before the presence of visitors we cleaned the beaches, during the stay of visitors we made the intervention (once or twice) in two out of the four beaches, and early next morning we estimated the amount of litter left per beach. Litter weight ranged from 0 to 53gvisitor-1day-1. Littering per visitor was reduced an average of 35% due to the intervention (p=0.049). We also found differences among beaches (p=0.001), and an increase in littering with crowding (p=0.005). We show for the first time that the personalized request combined with the example of picking up litter is effective in reducing littering in a Latin American country.